Short-Term Facilitation may Stabilize Parametric Working Memory Trace

1. Front Comput Neurosci. 2011 Oct 24;5:40. doi: 10.3389/fncom.2011.00040.
eCollection 2011.

Short-Term Facilitation may Stabilize Parametric Working Memory Trace.

Itskov V(1), Hansel D, Tsodyks M.

Author information:
(1)Department of Mathematics, University of Nebraska-Lincoln Lincoln, NE, USA.

Networks with continuous set of attractors are considered to be a paradigmatic
model for parametric working memory (WM), but require fine tuning of connections
and are thus structurally unstable. Here we analyzed the network with ring
attractor, where connections are not perfectly tuned and the activity state
therefore drifts in the absence of the stabilizing stimulus. We derive an
analytical expression for the drift dynamics and conclude that the network
cannot function as WM for a period of several seconds, a typical delay time in
monkey memory experiments. We propose that short-term synaptic facilitation in
recurrent connections significantly improves the robustness of the model by
slowing down the drift of activity bump. Extending the calculation of the drift
velocity to network with synaptic facilitation, we conclude that facilitation
can slow down the drift by a large factor, rendering the network suitable as a
model of WM.

DOI: 10.3389/fncom.2011.00040
PMCID: PMC3199447
PMID: 22028690

Auteurs Bordeaux Neurocampus